1. Field of the Invention
The present invention relates to a method and apparatus for synchronizing a time of day (TOD) of a terminal in a convergent network, and more particularly, to a method and apparatus for synchronizing the TOD, which adjusts synchronization between a time server and a terminal based on TOD information provided by a standard time server connected in a network.
2. Description of the Related Art
Terminals, such as computers, connected to a network include an internal clock, and maintain and manage TOD information.
The TOD information of the terminals may be different from actual time due to precision issues of the internal clock.
Accordingly, for the terminals to provide services at a common TOD in a network system, each terminal needs to quickly correct a time difference and synchronize the TOD.
A network time protocol (NTP) or a precision time protocol (PTP) is the basis for synchronizing the TOD over the Internet, and is a protocol for obtaining TOD information.
A terminal synchronizes the TOD by requesting the TOD from a TOD server that provides a standard time or from an NTP server, and by receiving a response signal from the TOD server or the NTP server.
Conventionally, TOD information provided from the NTP server or the TOD server to the terminal is included in general data.
FIG. 1 is a diagram illustrating a structure for synchronizing the TOD of a terminal 130 and a TOD server (or an NTP server) 100 connected in a conventional heterogeneous network.
A TOD gateway 120 is disposed between the TOD server 100 and the terminal 130, and converts data including TOD information to a data frame form according to characteristics of the terminal 130.
Functions of the TOD gateway 120 may be performed by a host PC.
The TOD gateway 120 converts the data including the TOD information received through an Ethernet or internet protocol (IP) network 110 to a data frame form so as to be recognized by the terminal 130.
The converting of the data performed by the TOD gateway 120 is performed in an open systems interconnection (OSI) 7th layer or a lower layer, and the data converted to the data frame form according to the characteristics of the terminal 130 is transmitted to the terminal 130 with the TOD information.
Upon receiving the data frame including the TOD information, the terminal 130 synchronizes the TOD by processing the TOD information using application software installed in the terminal 130.
Accordingly, throughput of a processor of the terminal 130 increases due to the processing of the application software, and an error may occur due to delay in processing the data frame.
When the throughput of the terminal 130 increases, a structure of the terminal 130 becomes complex and a cost of the terminal 130 also increases.